Pen



FIG. 1 is a front view of an embodiment of the present invention;

FIG. 2 is a front view of an embodiment of the present invention;

FIG. 3 is a rear view of an embodiment of the present invention;

FIG. 4 is a side view of an embodiment of the present invention; and,

FIG. 5 is a bottom view of an embodiment of the present invention. 

An ornamental design for a pen, as shown and described. 